1. My name is Olivia, and I was teased about my name only once, but I have to admit I had it coming at me; I wore a rather ugly green sweater on picture day in...wow, 7th grade maybe? So I was Olivia the olive for weeks. Haha. But I wasn't just randomly teased, it was common even then and I shared my name with 3 other girls in the grade. I'm gonna say no.
2. I don't have any children, but I occasionally work with a group of 6th grade students and I can think of instances where this has happened. One girl named Anja (not actually Dutch. lol), which is pronounced AWN-yuh, constantly has her name mispronounced and it obviously bugs her to no end, so of course people pronounce it like it's spelled just for her reaction. There was a Simone who dyed her hair mahogany (just streaks)...and she will be Mohogany for the rest of her life. We also have a boy named Tiger and a boy named Sunny. Oh, and Takahana gets Taco a lot. *rolls eyes*
3. Frankly, I don't think kids are actually teased about their names *that* much. It's almost an urban legend. I definitely think that Dorcas, Dick and other, similar names, should be avoided, but I don't think anybody should go out of their way to think of possible ways that every single name could be teased. (Oh no! Sofia could be Sofa! Scratch that!)
4a. I agree with this one, *but* as I said before I actually don't think kids are teased about their names very often. Of course, a Dick will be teased, as will Dorky Dorcas, and maybe even Loopy Lucy. However, this will sound mean but it's the truth, if the child is popular per se, then the other kids won't go out of their way. They won't even think about it.
4b. I wholeheartedly agree with this. I was popular growing up, kind of flighty, kind of ditsy, but sporty (I was on just about every sports team) and I had lots of friends, but their was the time in 7th grade (Olivia the Olive) and plenty of other little times to (the time when I ran into another girl on a rival gymnastics team, stood up, helped her up, apologized, and promptly tripped over her again). People make mistakes and they get teased for it. End of story. It doesn't matter who or what you are.
5. I do believe that they will draw more attention, but for a different reason, there will be no Melisandes in a class. but 2 or 3 Melanies, and infinite Sofia's. You can't just call one Sofia "Sofa", unless she's large and resembles a sofa in some form (can't imagine how one would resemble a sofa). Also, the examples you used are rather juvenile, a first grade playground sort of thing (no offense to your students!!)
6. Definitely. In the same 6th grade class, there's an Anja, a Takahana, a Simone, a Sebastian, a Claudia, a Shannon, an Adelina, a Mohammed, a Gino, a Sean, a Dante, a Safiya, and so on. None of these people (with the exception of Anja) has ever heard a word on their name. Some of them are more popular then others, but they span a range of origins. (There may be more worth noting, but none off the top of my head).